Effects of redox thermal treatments and feedstream composition on the activity of Ce/Zr mixed oxides for TWC applications

The activity of cerium/zirconium mixed oxides for TWC applications submitte d to different thermal treatments under oxidising, reducing and redox-cycle d atmospheres has been investigated. The effect of each individual reactant in the reaction system has been studied using feedstreams in which some co mponents had been removed and substituted by nitrogen. The conclusions extr acted from the individual reactions have been used to describe the role and effect of each reactant when all the components are present in the feedstr eam, and to explain the differences observed in the catalytic performance a fter different treatments. Finally, a Ce/Zr mixed oxide composition has bee n proposed as the best support for TWC applications. (C)2000 Elsevier Scien ce B.V. All rights reserved.